Optical devices that perform optical filtering and can be tuned to select one or more narrow band of wavelengths from a wider wavelength spectrum are known as tunable optical filters. They are used in a variety of optical systems, e.g., wavelength division multiplexed (WDM) systems. In WDM systems that operate typically over wavelength bands of tens of nanometers, tunable optical filters are used for optical performance monitoring (OPM) to ensure that signal power, signal wavelength, and/or signal to noise ratios (OSNR) are within specified limits. Other applications for tunable optical filters include optical noise filtering, noise suppression, wavelength division demultiplexing, and optical routing.
Complex state-of-the-art dense wavelength division multiplexed (DWDM) systems have many channels operating across a wide optical spectrum. Monitoring these channels is a challenge because many measurements are required. A monitoring equipment that reduces the time and complexity of performing these measurements can significantly increase overall system performance and reduce system costs.